Antenna



FIG. 1 is a top plan view of an antenna;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a rear plan view thereof;

FIG. 4 is top, front perspective view thereof;

FIG. 5 is another top plan view thereof shown with the base element removed for ease of illustration; and,

FIG. 6 is another left side elevational view thereof shown with the base element removed for ease of illustration.

The broken lines showing a base in FIGS. 1-4 represent environment and form no part of the claimed design. 

CLAIM The ornamental design for an antenna, as shown and described. 